1. Technical Field
The present disclosure relates to a wiring board and an electronic component device.
2. Description of the Related Art
In the related arts, wiring boards for mounting electronic components such as semiconductor chips are known. In such a wiring board, a terminal of a semiconductor chip is flip-chip connected to a pad exposed from an insulating layer (see e.g., U.S. Pat. No. 7,397,000 B2, U.S. Pat. No. 7,566,834 B2 and U.S. Pat. No. 8,772,951 B1).
As will be described in preliminary matters below, a pad is disposed in an insulating layer to sink internally downward from an upper surface of the insulating layer in a coreless type wiring board. Therefore, when a bump electrode of a semiconductor chip is flip-chip connected to the pad of the wiring board, a residue of a sealing resin material occurs in a connection portion easily.
In addition, assume that a metal post is formed on the pad of the coreless type wiring board. In this case, when the bump electrode of the semiconductor chip is connected to the pad of the wiring board by a solder, stress is concentrated on upper end corner portions of the metal post so that cracks occur easily in the solder.
Thus, there is a likelihood that satisfactory reliability in connection cannot be obtained when the semiconductor chip is flip-chip connected in the coreless type wiring board.